Java tutorial
/* * The MIT License (MIT) * * Copyright (c) 2014-2017 abel533@gmail.com * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package com.github.pagehelper.util; import com.github.pagehelper.Dialect; import com.github.pagehelper.PageException; import org.apache.ibatis.cache.CacheKey; import org.apache.ibatis.executor.Executor; import org.apache.ibatis.mapping.BoundSql; import org.apache.ibatis.mapping.MappedStatement; import org.apache.ibatis.session.Configuration; import org.apache.ibatis.session.ResultHandler; import org.apache.ibatis.session.RowBounds; import java.lang.reflect.Field; import java.sql.SQLException; import java.util.List; import java.util.Map; /** * @author liuzenghui */ public abstract class ExecutorUtil { private static Field additionalParametersField; static { try { additionalParametersField = BoundSql.class.getDeclaredField("additionalParameters"); additionalParametersField.setAccessible(true); } catch (NoSuchFieldException e) { throw new PageException("? BoundSql additionalParameters : " + e, e); } } /** * ? BoundSql additionalParameters * * @param boundSql * @return */ public static Map<String, Object> getAdditionalParameter(BoundSql boundSql) { try { return (Map<String, Object>) additionalParametersField.get(boundSql); } catch (IllegalAccessException e) { throw new PageException("? BoundSql additionalParameters : " + e, e); } } /** * ??? MS??countpage? * * @param configuration * @param msId * @return */ public static MappedStatement getExistedMappedStatement(Configuration configuration, String msId) { MappedStatement mappedStatement = null; try { mappedStatement = configuration.getMappedStatement(msId, false); } catch (Throwable t) { //ignore } return mappedStatement; } /** * count ??? * * @param executor * @param countMs * @param parameter * @param boundSql * @param resultHandler * @return * @throws SQLException */ public static Long executeManualCount(Executor executor, MappedStatement countMs, Object parameter, BoundSql boundSql, ResultHandler resultHandler) throws SQLException { CacheKey countKey = executor.createCacheKey(countMs, parameter, RowBounds.DEFAULT, boundSql); BoundSql countBoundSql = countMs.getBoundSql(parameter); Object countResultList = executor.query(countMs, parameter, RowBounds.DEFAULT, resultHandler, countKey, countBoundSql); Long count = ((Number) ((List) countResultList).get(0)).longValue(); return count; } /** * ? count * * @param dialect * @param executor * @param countMs * @param parameter * @param boundSql * @param rowBounds * @param resultHandler * @return * @throws SQLException */ public static Long executeAutoCount(Dialect dialect, Executor executor, MappedStatement countMs, Object parameter, BoundSql boundSql, RowBounds rowBounds, ResultHandler resultHandler) throws SQLException { Map<String, Object> additionalParameters = getAdditionalParameter(boundSql); // count key CacheKey countKey = executor.createCacheKey(countMs, parameter, RowBounds.DEFAULT, boundSql); //? count sql String countSql = dialect.getCountSql(countMs, boundSql, parameter, rowBounds, countKey); //countKey.update(countSql); BoundSql countBoundSql = new BoundSql(countMs.getConfiguration(), countSql, boundSql.getParameterMappings(), parameter); //? SQL ???? BoundSql for (String key : additionalParameters.keySet()) { countBoundSql.setAdditionalParameter(key, additionalParameters.get(key)); } // count Object countResultList = executor.query(countMs, parameter, RowBounds.DEFAULT, resultHandler, countKey, countBoundSql); Long count = (Long) ((List) countResultList).get(0); return count; } /** * * * @param dialect * @param executor * @param ms * @param parameter * @param rowBounds * @param resultHandler * @param boundSql * @param cacheKey * @param <E> * @return * @throws SQLException */ public static <E> List<E> pageQuery(Dialect dialect, Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql, CacheKey cacheKey) throws SQLException { //?? if (dialect.beforePage(ms, parameter, rowBounds)) { //? key CacheKey pageKey = cacheKey; //?? parameter = dialect.processParameterObject(ms, parameter, boundSql, pageKey); //? sql String pageSql = dialect.getPageSql(ms, boundSql, parameter, rowBounds, pageKey); BoundSql pageBoundSql = new BoundSql(ms.getConfiguration(), pageSql, boundSql.getParameterMappings(), parameter); Map<String, Object> additionalParameters = getAdditionalParameter(boundSql); //?? for (String key : additionalParameters.keySet()) { pageBoundSql.setAdditionalParameter(key, additionalParameters.get(key)); } // return executor.query(ms, parameter, RowBounds.DEFAULT, resultHandler, pageKey, pageBoundSql); } else { //?? return executor.query(ms, parameter, RowBounds.DEFAULT, resultHandler, cacheKey, boundSql); } } }